The association between thyroid function and left ventricular hypertrophy

Background: Left ventricular hypertrophy predicts cardiovascular mortality. The role of thyroid function for its development has not been completely elucidated. Decreased serum thyrotropin predicts vascular mortality in elderly people, which hypothetically could be explained by left ventricular hypertrophy. The aim of this analysis was to investigate the association between thyroid function and left ventricular hypertrophy.

Methods and Results: The population-based Study of Health in Pomerania (SHIP) was conducted in a previously iodine-deficient area. The study included 4.310 participants aged 20 to 79 years. Data of 1510 individuals ≥45 years (684 women, 826 men) with echocardiography and without known thyroid disorder were available for this analysis. Twenty-three participants (1.5%) were hypothyroid, 1279 (84.7%) were euthyroid, 201 (13.3%) had subclinical and 7 (0.5%) had overt hyperthyroidism. Left ventricular hypertrophy was defined as a left ventricular mass of >294g in men and of >198g in women. Analysis revealed a direct correlation between thyroid function and left ventricular hypertrophy. Lowest values of left ventricular mass were found in participants with hypothyroidism, while hyperthyroid people had highest values (p<0.01). Left ventricular hypertrophy was observed in 4 (20.0%) hypothyroid, 182 (15.0%) euthyroid, 32 (16.7%) subclinical hyperthyroid and in 5 (71.4%) hyperthyroid individuals (p<0.01). Logistic regression analysis identified hyperthyroidism as an independent risk factor for left ventricular hypertrophy (odds ratio 19.03, 95%-confidence interval 3.5–104.7) compared to euthyroidism. Further risk factors were male gender, advanced age, increased body mass index and hypertension.

Conclusion: There is an association between thyroid function status and left ventricular hypertrophy. Hyperthyroidism was shown as an independent risk factor for left ventricular hypertrophy.